Preoperative evaluation and intraoperative protection of the facial nerve in congenital aural atresia.

We conducted a prospective study to assess the value of high-resolution computed tomography (HRCT) in identifying facial nerve variations in patients with congenital aural atresia and to determine how they affect otologic reconstruction surgery. Our study population was made up of 65 patients (69 ears) aged 6 to 22 years (mean: 13.7) without regard to sex. They were classified into three groups according to their scores on the Jahrsdoerfer grading scale: 46 ears scored 8 or more, 18 had a score of 6 or 7, and 5 scored 5 or less. The course of each facial nerve as determined intraoperatively was compared with the preoperative HRCT findings. HRCT revealed that in most of the facial nerves, the tympanic segments overlapped the oval window partly or completely; this was confirmed by surgical findings in most cases. Three of the 69 facial nerves (4.3%) were bifurcated. It is interesting that in 1 ear in which the facial nerve completely covered the oval window, the angle of the second genu was acute, exhibiting a "sharp turn." We conclude that HRCT is undoubtedly of value in identifying the course of the facial nerve and is of critical importance in helping surgeons make correct decisions in otologic reconstruction surgery.